The present invention relates to a shutter for a half circle or arched window in general and in particular to a spring suspension of individual slats in the shutter.
Venetian blinds are used to prevent direct sunlight from entering a house or other building and are typically made of a number of parallel rectangular slats or blades, each of which are supported by one of the rungs of a ladder-shaped fabric segment installed at each end of the blades. Venetian blinds are therefore limited to an essentially rectangular configuration. Arched or semi-circular windows are popular in many types of architectural design creating a need for a covering to prevent the passage of direct sunlight through the window.
Shutters for half circle or arched windows present problems involving the size, shape, weight and ability to interlock of the slats which are not associated with the more common venetian blinds. The prior art involving inventions for covering circular or half-circular openings fall into two general categories. The first category utilizes blinds or slats which pivot from a common point. U.S. Pat. No. 492,671 discloses a cinder, dust and smoke excluder for car windows having beveled triangular plates which pivot like fan. U.S. Pat. No. 602,967 discloses collapsible blinds for circular or arched windows comprising two fan shaped collapsible blinds with slats pivotally connected near the center of the circle forming the arch. U.S. Pat. No. 1,060,187 discloses a wind shield for automobiles radiators having triangular blades with flaring sides which rotate from a common pivot point. U.S. Pat. No. 4,776,380 discloses two sets of blades which fan out from the ends of a U-shaped frame and meet at the top of the frame. U.S. Pat. No. 4,699,195 discloses a collapsible blind for semi-circular arched windows with tapered blades that fan out from a common axis of rotation. U.S. Pat. No. 4,934,4334, U.S. Pat. No. 4,934,436 and U.S. Pat. No. 5,002,112 disclose pleated or multi-cellular shade fabric which deploy fanlike from a common point. U.S. Pat. No. 5,117,889 discloses a blind with slats attached to a pivot bolt. U.S. Pat. No. 5,584,329 discloses a moveable shade for arched windows with triangular type blades with center ends attached pivotally at a bottom center of a window arc and outside ends rotated from the bottom outside edges of the arc to a top center of the arc.
The second category of prior art inventions for covering circular or half-circular openings involves linear pivoting. For decorative purposes, linear pivoting is most desirable because when the blades or slats are in a closed position the surface presented will be flat. By linear pivoting is meant that each blade or slat is connected to a support so that the blade or slat rotates about the axis of the two points of connection. The blades or slats must be rotatable connected to a semi-circular base and a semi-circular top support. U.S. Pat. No. 4,936,048 discloses a swivel shutter with slats pivotally mounted in a rectangular frame. U.S. Pat. No. 1,447,189 discloses linear pivoting of slats in a manner similar to the pitch adjustment of a propeller in an semi-circular frame.
The advent of lightweight materials such as foam polyvinyl chloride make the construction of lightweight shutters for arched windows possible. Likewise, composite materials such as bonded sawdust and resin provide lightweight construction materials. Additionally, both foam PVC and composite materials covered with a thin plastic skin provide materials which also allow a wide range of colors for matching to the installation site. Half-circle windows normally are installed above a rectangular window. Therefore, a further advantage of these lightweight materials and the ability to match colors is that the half circle shutter can be utilized in conjunction with either shutters or blinds on the rectangular window. The ability to match a half circle shutter with Venetian blinds as well as shutters provides for a wide range of adaptability of the arched shutter/blind. Finally, these lightweight materials allow a wide variety of pre-fabricated shutters for arched windows to be mass-produced thereby keeping costs down while maintaining a high quality appearance.
However, problems arise in constructing a semi-circular shutter out of such lightweight materials when linear pivoting of each slat is employed. Each slat must be anchored in a top support and a bottom support. Slats can be formed from composite materials with prongs at either end for mating with holes in the base and the top support. The first problem that arises is that, on larger shutters, the semi-circular top support can deform in handling so that the blades may become detached and fall out. For example, if the arched shutter is lifted by the top support it may deform slightly increasing the distance between the top support and bottom support to the point where the distance exceeds the length of the top prong of one or more slats. Another problem arises in keeping the tops of the blades uniformly aligned with the top support. Minor variations in the shape of the arch of the top support will be noticeable if the distance between the top of the slats and the top support varies. Moreover, such non-uniform distances will not only detract from the appearance but will also increase light leakage between the slats and the support. An additional problem that arises in mass manufacturing shutters for semi-circular windows is to increase the range of window sizes to which one shutter for a semi-circular window can be affixed. For example, the top support has a front decorative trim element that covers the space between the top support and the arch of the wall around the window to be shuttered. The wall arch is usually not geometrically perfect and can vary considerably from window to window. Thus the front decorative trim of the top support covers the intervening space. Additionally, the front decorative trim allows for a range of window sizes to be serviced by one shutter size. The larger the area of the front decorative trim the greater the range of window sizes that can be serviced by one arched shutter. A further problem in constructing arched blinds with linearly pivoting slats is to maintain a smooth surface appearance with the slats are closed while minimizing light leakage between the slats. If the slats are made to overlap they will not lie in the same plane when closed thereby distracting from the desired appearance. Finally, there exists a need for the slats to be capable of being individually turned and for each slats to remain in the position to which each individual slat has been turned. The prior art does not address these problems. Therefore, what is needed beyond the prior art is a semi-circular shutter that can be constructed of lightweight materials (1) so the slats will not fall out when the shutter is lifted or moved due to deformation of the outer frame, (2) so that light leakage between the slats and between the slats and the support will be minimized, (3) so that the shutter is adaptable to a range of arched window sizes, and (4) so that the individual slats can be turned and remain in position.
The present invention which meets the needs identified above is a shutter for half-circle window having a top, a base, and a plurality of slats capable of interlocking engagement and rotatably secured between the top and the base wherein the slats are further held in position by springs providing pressure against the slats.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention.